[dpdk-dev,v3,1/2] eal: add API to align integer to previous power of 2
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Commit Message
Add 32b and 64b API's to align the given integer to the previous power
of 2.
Signed-off-by: Pavan Nikhilesh <pbhagavatula@caviumnetworks.com>
---
v3 Changes:
- Move commonly used code to rte_combine(32/64)ms1b so that it can be reused.
v2 Changes:
- Modified api name to `rte_align(32/64)prevpow2` from
`rte_align(32/64)lowpow2`.
- corrected fuction to return if the integer is already aligned to
power of 2.
lib/librte_eal/common/include/rte_common.h | 92 ++++++++++++++++++++++++++----
1 file changed, 81 insertions(+), 11 deletions(-)
--
2.16.3
Comments
Hi Pavan
Shouldn't the new APIs be tagged with the experimental tag as agreed?
Besides that,
Acked-by: Matan Azrad <matan@mellanox.com>
From: Pavan Nikhilesh, Wednesday, April 4, 2018 1:16 PM
> Add 32b and 64b API's to align the given integer to the previous power of 2.
>
> Signed-off-by: Pavan Nikhilesh <pbhagavatula@caviumnetworks.com>
> ---
> v3 Changes:
> - Move commonly used code to rte_combine(32/64)ms1b so that it can be
> reused.
>
> v2 Changes:
> - Modified api name to `rte_align(32/64)prevpow2` from
> `rte_align(32/64)lowpow2`.
> - corrected fuction to return if the integer is already aligned to power of 2.
>
> lib/librte_eal/common/include/rte_common.h | 92
> ++++++++++++++++++++++++++----
> 1 file changed, 81 insertions(+), 11 deletions(-)
>
> diff --git a/lib/librte_eal/common/include/rte_common.h
> b/lib/librte_eal/common/include/rte_common.h
> index c7803e41c..7e147dcf2 100644
> --- a/lib/librte_eal/common/include/rte_common.h
> +++ b/lib/librte_eal/common/include/rte_common.h
> @@ -223,6 +223,51 @@ extern int RTE_BUILD_BUG_ON_detected_error; }
> while(0) #endif
>
> +/**
> + * Combines 32b inputs most significant set bits into the least
> + * significant bits to construct a value with the same MSBs as x
> + * but all 1's under it.
> + *
> + * @param x
> + * The integer whose MSBs need to be combined with its LSBs
> + * @return
> + * The combined value.
> + */
> +static inline uint32_t
> +rte_combine32ms1b(register uint32_t x)
> +{
> + x |= x >> 1;
> + x |= x >> 2;
> + x |= x >> 4;
> + x |= x >> 8;
> + x |= x >> 16;
> +
> + return x;
> +}
> +
> +/**
> + * Combines 64b inputs most significant set bits into the least
> + * significant bits to construct a value with the same MSBs as x
> + * but all 1's under it.
> + *
> + * @param v
> + * The integer whose MSBs need to be combined with its LSBs
> + * @return
> + * The combined value.
> + */
> +static inline uint64_t
> +rte_combine64ms1b(register uint64_t v)
> +{
> + v |= v >> 1;
> + v |= v >> 2;
> + v |= v >> 4;
> + v |= v >> 8;
> + v |= v >> 16;
> + v |= v >> 32;
> +
> + return v;
> +}
> +
> /*********** Macros to work with powers of 2 ********/
>
> /**
> @@ -250,15 +295,28 @@ static inline uint32_t rte_align32pow2(uint32_t x) {
> x--;
> - x |= x >> 1;
> - x |= x >> 2;
> - x |= x >> 4;
> - x |= x >> 8;
> - x |= x >> 16;
> + x = rte_combine32ms1b(x);
>
> return x + 1;
> }
>
> +/**
> + * Aligns input parameter to the previous power of 2
> + *
> + * @param x
> + * The integer value to algin
> + *
> + * @return
> + * Input parameter aligned to the previous power of 2
> + */
> +static inline uint32_t
> +rte_align32prevpow2(uint32_t x)
> +{
> + x = rte_combine32ms1b(x);
> +
> + return x - (x >> 1);
> +}
> +
> /**
> * Aligns 64b input parameter to the next power of 2
> *
> @@ -272,16 +330,28 @@ static inline uint64_t rte_align64pow2(uint64_t v) {
> v--;
> - v |= v >> 1;
> - v |= v >> 2;
> - v |= v >> 4;
> - v |= v >> 8;
> - v |= v >> 16;
> - v |= v >> 32;
> + v = rte_combine64ms1b(v);
>
> return v + 1;
> }
>
> +/**
> + * Aligns 64b input parameter to the previous power of 2
> + *
> + * @param v
> + * The 64b value to align
> + *
> + * @return
> + * Input parameter aligned to the previous power of 2
> + */
> +static inline uint64_t
> +rte_align64prevpow2(uint64_t v)
> +{
> + v = rte_combine64ms1b(v);
> +
> + return v - (v >> 1);
> +}
> +
> /*********** Macros for calculating min and max **********/
>
> /**
> --
> 2.16.3
Hi Matan,
On Wed, Apr 04, 2018 at 04:10:36PM +0000, Matan Azrad wrote:
> Hi Pavan
>
> Shouldn't the new APIs be tagged with the experimental tag as agreed?
Can't tag it experimental as it causes cyclic dependency (need to include
rte_compact.h).
Besides it's a simple proven math API I don't think it will change anytime
soon.
Thanks,
Pavan
>
> Besides that,
> Acked-by: Matan Azrad <matan@mellanox.com>
>
> From: Pavan Nikhilesh, Wednesday, April 4, 2018 1:16 PM
> > Add 32b and 64b API's to align the given integer to the previous power of 2.
> >
> > Signed-off-by: Pavan Nikhilesh <pbhagavatula@caviumnetworks.com>
> > ---
> > v3 Changes:
> > - Move commonly used code to rte_combine(32/64)ms1b so that it can be
> > reused.
> >
> > v2 Changes:
> > - Modified api name to `rte_align(32/64)prevpow2` from
> > `rte_align(32/64)lowpow2`.
> > - corrected fuction to return if the integer is already aligned to power of 2.
> >
> > lib/librte_eal/common/include/rte_common.h | 92
> > ++++++++++++++++++++++++++----
> > 1 file changed, 81 insertions(+), 11 deletions(-)
> >
> > diff --git a/lib/librte_eal/common/include/rte_common.h
> > b/lib/librte_eal/common/include/rte_common.h
> > index c7803e41c..7e147dcf2 100644
> > --- a/lib/librte_eal/common/include/rte_common.h
> > +++ b/lib/librte_eal/common/include/rte_common.h
> > @@ -223,6 +223,51 @@ extern int RTE_BUILD_BUG_ON_detected_error; }
> > while(0) #endif
> >
> > +/**
> > + * Combines 32b inputs most significant set bits into the least
> > + * significant bits to construct a value with the same MSBs as x
> > + * but all 1's under it.
> > + *
> > + * @param x
> > + * The integer whose MSBs need to be combined with its LSBs
> > + * @return
> > + * The combined value.
> > + */
> > +static inline uint32_t
> > +rte_combine32ms1b(register uint32_t x)
> > +{
> > + x |= x >> 1;
> > + x |= x >> 2;
> > + x |= x >> 4;
> > + x |= x >> 8;
> > + x |= x >> 16;
> > +
> > + return x;
> > +}
> > +
> > +/**
> > + * Combines 64b inputs most significant set bits into the least
> > + * significant bits to construct a value with the same MSBs as x
> > + * but all 1's under it.
> > + *
> > + * @param v
> > + * The integer whose MSBs need to be combined with its LSBs
> > + * @return
> > + * The combined value.
> > + */
> > +static inline uint64_t
> > +rte_combine64ms1b(register uint64_t v)
> > +{
> > + v |= v >> 1;
> > + v |= v >> 2;
> > + v |= v >> 4;
> > + v |= v >> 8;
> > + v |= v >> 16;
> > + v |= v >> 32;
> > +
> > + return v;
> > +}
> > +
> > /*********** Macros to work with powers of 2 ********/
> >
> > /**
> > @@ -250,15 +295,28 @@ static inline uint32_t rte_align32pow2(uint32_t x) {
> > x--;
> > - x |= x >> 1;
> > - x |= x >> 2;
> > - x |= x >> 4;
> > - x |= x >> 8;
> > - x |= x >> 16;
> > + x = rte_combine32ms1b(x);
> >
> > return x + 1;
> > }
> >
> > +/**
> > + * Aligns input parameter to the previous power of 2
> > + *
> > + * @param x
> > + * The integer value to algin
> > + *
> > + * @return
> > + * Input parameter aligned to the previous power of 2
> > + */
> > +static inline uint32_t
> > +rte_align32prevpow2(uint32_t x)
> > +{
> > + x = rte_combine32ms1b(x);
> > +
> > + return x - (x >> 1);
> > +}
> > +
> > /**
> > * Aligns 64b input parameter to the next power of 2
> > *
> > @@ -272,16 +330,28 @@ static inline uint64_t rte_align64pow2(uint64_t v) {
> > v--;
> > - v |= v >> 1;
> > - v |= v >> 2;
> > - v |= v >> 4;
> > - v |= v >> 8;
> > - v |= v >> 16;
> > - v |= v >> 32;
> > + v = rte_combine64ms1b(v);
> >
> > return v + 1;
> > }
> >
> > +/**
> > + * Aligns 64b input parameter to the previous power of 2
> > + *
> > + * @param v
> > + * The 64b value to align
> > + *
> > + * @return
> > + * Input parameter aligned to the previous power of 2
> > + */
> > +static inline uint64_t
> > +rte_align64prevpow2(uint64_t v)
> > +{
> > + v = rte_combine64ms1b(v);
> > +
> > + return v - (v >> 1);
> > +}
> > +
> > /*********** Macros for calculating min and max **********/
> >
> > /**
> > --
> > 2.16.3
>
From: Pavan Nikhilesh, Wednesday, April 4, 2018 7:42 PM
> Hi Matan,
>
> On Wed, Apr 04, 2018 at 04:10:36PM +0000, Matan Azrad wrote:
> > Hi Pavan
> >
> > Shouldn't the new APIs be tagged with the experimental tag as agreed?
>
> Can't tag it experimental as it causes cyclic dependency (need to include
> rte_compact.h).
You probably mean rte_compat.h.
It is ok to add it, what is the issue with that?
> Besides it's a simple proven math API I don't think it will change anytime
> soon.
It has already discussed:
https://dpdk.org/dev/patchwork/patch/35211/
I think you need to add it anyway.
> Thanks,
> Pavan
>
> >
> > Besides that,
> > Acked-by: Matan Azrad <matan@mellanox.com>
> >
> > From: Pavan Nikhilesh, Wednesday, April 4, 2018 1:16 PM
> > > Add 32b and 64b API's to align the given integer to the previous power of
> 2.
> > >
> > > Signed-off-by: Pavan Nikhilesh <pbhagavatula@caviumnetworks.com>
> > > ---
> > > v3 Changes:
> > > - Move commonly used code to rte_combine(32/64)ms1b so that it can
> > > be reused.
> > >
> > > v2 Changes:
> > > - Modified api name to `rte_align(32/64)prevpow2` from
> > > `rte_align(32/64)lowpow2`.
> > > - corrected fuction to return if the integer is already aligned to power of
> 2.
> > >
> > > lib/librte_eal/common/include/rte_common.h | 92
> > > ++++++++++++++++++++++++++----
> > > 1 file changed, 81 insertions(+), 11 deletions(-)
> > >
> > > diff --git a/lib/librte_eal/common/include/rte_common.h
> > > b/lib/librte_eal/common/include/rte_common.h
> > > index c7803e41c..7e147dcf2 100644
> > > --- a/lib/librte_eal/common/include/rte_common.h
> > > +++ b/lib/librte_eal/common/include/rte_common.h
> > > @@ -223,6 +223,51 @@ extern int
> RTE_BUILD_BUG_ON_detected_error; }
> > > while(0) #endif
> > >
> > > +/**
> > > + * Combines 32b inputs most significant set bits into the least
> > > + * significant bits to construct a value with the same MSBs as x
> > > + * but all 1's under it.
> > > + *
> > > + * @param x
> > > + * The integer whose MSBs need to be combined with its LSBs
> > > + * @return
> > > + * The combined value.
> > > + */
> > > +static inline uint32_t
> > > +rte_combine32ms1b(register uint32_t x) {
> > > + x |= x >> 1;
> > > + x |= x >> 2;
> > > + x |= x >> 4;
> > > + x |= x >> 8;
> > > + x |= x >> 16;
> > > +
> > > + return x;
> > > +}
> > > +
> > > +/**
> > > + * Combines 64b inputs most significant set bits into the least
> > > + * significant bits to construct a value with the same MSBs as x
> > > + * but all 1's under it.
> > > + *
> > > + * @param v
> > > + * The integer whose MSBs need to be combined with its LSBs
> > > + * @return
> > > + * The combined value.
> > > + */
> > > +static inline uint64_t
> > > +rte_combine64ms1b(register uint64_t v) {
> > > + v |= v >> 1;
> > > + v |= v >> 2;
> > > + v |= v >> 4;
> > > + v |= v >> 8;
> > > + v |= v >> 16;
> > > + v |= v >> 32;
> > > +
> > > + return v;
> > > +}
> > > +
> > > /*********** Macros to work with powers of 2 ********/
> > >
> > > /**
> > > @@ -250,15 +295,28 @@ static inline uint32_t rte_align32pow2(uint32_t
> x) {
> > > x--;
> > > - x |= x >> 1;
> > > - x |= x >> 2;
> > > - x |= x >> 4;
> > > - x |= x >> 8;
> > > - x |= x >> 16;
> > > + x = rte_combine32ms1b(x);
> > >
> > > return x + 1;
> > > }
> > >
> > > +/**
> > > + * Aligns input parameter to the previous power of 2
> > > + *
> > > + * @param x
> > > + * The integer value to algin
> > > + *
> > > + * @return
> > > + * Input parameter aligned to the previous power of 2
> > > + */
> > > +static inline uint32_t
> > > +rte_align32prevpow2(uint32_t x)
> > > +{
> > > + x = rte_combine32ms1b(x);
> > > +
> > > + return x - (x >> 1);
> > > +}
> > > +
> > > /**
> > > * Aligns 64b input parameter to the next power of 2
> > > *
> > > @@ -272,16 +330,28 @@ static inline uint64_t rte_align64pow2(uint64_t
> v) {
> > > v--;
> > > - v |= v >> 1;
> > > - v |= v >> 2;
> > > - v |= v >> 4;
> > > - v |= v >> 8;
> > > - v |= v >> 16;
> > > - v |= v >> 32;
> > > + v = rte_combine64ms1b(v);
> > >
> > > return v + 1;
> > > }
> > >
> > > +/**
> > > + * Aligns 64b input parameter to the previous power of 2
> > > + *
> > > + * @param v
> > > + * The 64b value to align
> > > + *
> > > + * @return
> > > + * Input parameter aligned to the previous power of 2
> > > + */
> > > +static inline uint64_t
> > > +rte_align64prevpow2(uint64_t v)
> > > +{
> > > + v = rte_combine64ms1b(v);
> > > +
> > > + return v - (v >> 1);
> > > +}
> > > +
> > > /*********** Macros for calculating min and max **********/
> > >
> > > /**
> > > --
> > > 2.16.3
> >
@@ -223,6 +223,51 @@ extern int RTE_BUILD_BUG_ON_detected_error;
} while(0)
#endif
+/**
+ * Combines 32b inputs most significant set bits into the least
+ * significant bits to construct a value with the same MSBs as x
+ * but all 1's under it.
+ *
+ * @param x
+ * The integer whose MSBs need to be combined with its LSBs
+ * @return
+ * The combined value.
+ */
+static inline uint32_t
+rte_combine32ms1b(register uint32_t x)
+{
+ x |= x >> 1;
+ x |= x >> 2;
+ x |= x >> 4;
+ x |= x >> 8;
+ x |= x >> 16;
+
+ return x;
+}
+
+/**
+ * Combines 64b inputs most significant set bits into the least
+ * significant bits to construct a value with the same MSBs as x
+ * but all 1's under it.
+ *
+ * @param v
+ * The integer whose MSBs need to be combined with its LSBs
+ * @return
+ * The combined value.
+ */
+static inline uint64_t
+rte_combine64ms1b(register uint64_t v)
+{
+ v |= v >> 1;
+ v |= v >> 2;
+ v |= v >> 4;
+ v |= v >> 8;
+ v |= v >> 16;
+ v |= v >> 32;
+
+ return v;
+}
+
/*********** Macros to work with powers of 2 ********/
/**
@@ -250,15 +295,28 @@ static inline uint32_t
rte_align32pow2(uint32_t x)
{
x--;
- x |= x >> 1;
- x |= x >> 2;
- x |= x >> 4;
- x |= x >> 8;
- x |= x >> 16;
+ x = rte_combine32ms1b(x);
return x + 1;
}
+/**
+ * Aligns input parameter to the previous power of 2
+ *
+ * @param x
+ * The integer value to algin
+ *
+ * @return
+ * Input parameter aligned to the previous power of 2
+ */
+static inline uint32_t
+rte_align32prevpow2(uint32_t x)
+{
+ x = rte_combine32ms1b(x);
+
+ return x - (x >> 1);
+}
+
/**
* Aligns 64b input parameter to the next power of 2
*
@@ -272,16 +330,28 @@ static inline uint64_t
rte_align64pow2(uint64_t v)
{
v--;
- v |= v >> 1;
- v |= v >> 2;
- v |= v >> 4;
- v |= v >> 8;
- v |= v >> 16;
- v |= v >> 32;
+ v = rte_combine64ms1b(v);
return v + 1;
}
+/**
+ * Aligns 64b input parameter to the previous power of 2
+ *
+ * @param v
+ * The 64b value to align
+ *
+ * @return
+ * Input parameter aligned to the previous power of 2
+ */
+static inline uint64_t
+rte_align64prevpow2(uint64_t v)
+{
+ v = rte_combine64ms1b(v);
+
+ return v - (v >> 1);
+}
+
/*********** Macros for calculating min and max **********/
/**